This invention relates to a valve assembly wherein a valve element is selectively positioned within a flow passage to control fluid flow through the flow passage and the selective positioning of the valve element is performed by means of an actuator comprising a chamber space that is expanded and contracted in volume by introduction and removal of control fluid into and from the chamber space.
A preliminary novelty search developed the following U.S. Pat. Nos. 826,637; 1,048,228; 1,624,348; 2,213,785; 3,918,421; 4,070,001; and 4,367,764.
In prior valves, the valve element, the expansible and contractible chamber space, and the coupling of the chamber space to the valve element comprise an assembly of several parts.
In contrast to prior valves and actuators, the present invention provides the valve element, the expansible and contractible chamber space, and the coupling of the chamber space to the valve element in a single plastic part. The single part can be fabricated by a conventional blow-molding process. The single part is made to be resiliently flexible in the region of its expansible and contractible chamber space and to be stiff elsewhere. One way of imparting these characteristics to respective regions of the single part is by the particular design and dimensioning (e.g. thickness) of the different regions. The particular material that is used to fabricate the part may also have an influence on the performance characteristics of the part.
One of the significant advantages of the invention is that the valve assembly can be constructed from a fewer number of individual parts. This simplification has favorable cost implications, especially when the invention is embodied in the thermal valve of the air induction system of an automotive internal combustion engine. Prior thermal valves usually require a vacuum actuator (itself having several parts), a flap door (valve element), and a connecting rod.
Further features, benefits, and advantages of the invention will be seen in the ensuing detailed description of a preferred embodiment. Drawings accompany the disclosure and illustrate the best mode contemplated at this time for putting the preferred embodiment into practice.